Pony vs larger tank?

[waynne fowler]

I am thinking about redundancy and such and have considered getting a pony bottle. I went into a LDS and was looking at some new gear and asked about it. Well the guy doesn't have pony bottles in stock (not at the size I was looking for) and told me I should just buy a larger tank.

Here was his thinking (besides selling what he had in stock); If your reg malfunctions then it will have to break in the open position and you have free flow. He then asked the obvious 'You do know you can still breath on a free flowing reg don't you?'

OK, I get his point but I still don't think it is as best as having a completely seperate setup but I wanted to hear back from people who may know better then me.

Just the FYI part as it may be important. I currently dive Al80's, warm water only (gulf coast of the USA or further south) with a typical dive between 40ish and 80ish feet. I was thinking a small 13 would be enough to get me from max bottom of 80 to surface with a short safety stop.

I am not sure I buy the bigger tank theory (moving up to a 100) as I am not sure how quickly the air could escape. If I am at the end of my dive and something goes wrong would I still have enough air to make a safety stop?

Thoughts?

I've seen free flows and lp hose ruptures empty full 100 and 80 cf tank in under 3 mins. I think your on the right track of a completly independant system. Though for me I choose to use a 30 or a 40 cf tank and just sling it. I like the ability to pass it off to another diver if need be. Check I think you'll find moving to a 19 cf pony won't cost you more than 10 - 25 xtra on the tank itself.

 

[Bonairetrip]

IMHO, there are three options for redundant air:
a) Doubles with an isolation valve & two regs. (OP was not asking about this)
b) A reliable buddy. (OP was not asking about this)
c) A pony.

The major questions with a pony:
a) How large;
b) How is it rigged.

Both have been covered well.

 

[I Dive]

Here was his thinking (besides selling what he had in stock); If your reg malfunctions then it will have to break in the open position and you have free flow. He then asked the obvious 'You do know you can still breath on a free flowing reg don't you?'
Thoughts?

Well, there we have it. Buddy breathing, Sharing air, Doubles diving, Pony bottles, and other forms of redundancy I haven't thought of yet are all wastes of time, effort, and money. A reg fails in your favor so that's all you need! Just dive an 8000 CF cylinder and you should have no worries!

 

[DaleC]

IMHO, there are three options for redundant air:
a) Doubles with an isolation valve & two regs. (OP was not asking about this)
b) A reliable buddy. (OP was not asking about this)
c) A pony.

The major questions with a pony:
a) How large;
b) How is it rigged.

Both have been covered well.

What's wrong with independant twins as a redundant air source?

 

[drdaddy]

I dive HP steel 3442s 100s. I use a pony attached to my main tank. It is turned on before I enter the water. I have tried slinging the pony, but it gets in the way and drags as I'm chasing dungeness crabs. Many of my dives are jetty dives and are less than 50 feet deep, so 13 cuft is adequate, and anything deeper I'd recommend 19 cuft. However, I like to always be diving with the same equipment so I'm familiar with it and work out all the bugs, so I dive with my 19 cuft pony at all depths (well maybe not at the 12-15 ft Alsea-Waldport, Oregon crab dives).

Sometimes I'll dive with my steel HP 3442s 80s, but I like the extra few minutes that the 100s give. I also keep my AL 80s up to date to loan to friends who have not yet discovered steel.

A warning about pony bottles. They do not attach to your BCD, so will not inflate it. Practice OOAir situations so you will be familiar with the drill.

drdaddy

 

[Sinbad the Diver]

I go with the idea that a pony is an emergency item and is not included in your dive plan gas calculations. It is there to give you a second chance if you have failures or if you simply make a mistake and need air. If you buy a bigger tank, you've extended your dive time, but you haven't accounted for emergencies.

 

[waynne fowler]

Well, there we have it. Buddy breathing, Sharing air, Doubles diving, Pony bottles, and other forms of redundancy I haven't thought of yet are all wastes of time, effort, and money. A reg fails in your favor so that's all you need! Just dive an 8000 CF cylinder and you should have no worries!

shoot.... have two! Get 10 or 20000 feet of hose... heck!
on top of never worrying about running OOA just think, you'd never NOT find your way back to your entry! No compass needed!

 

[drdaddy]

To the OP: I went through the same thoughts last year and ended up getting a 19CF pony. I use an x-bracket to mount it on my main tank.

Dislikes: It took some getting used to: I don't like the extra weight on the surface, and it threw me off balance for several dives until I got my weighting just right. I don't like the x-bracket either because it is cumbersome to use. (I've tried other mounting solutions, the x-bracket is the least sucky, so far.). It makes my boat dives harder: I often dive off a panga and pulling my rig over the side is much harder with the pony attached.

Likes: I'm glad I picked 19CF. I was considering 13CF and really wanted the smaller, lighter pony. Since I test the reg before every dive, and sometimes the reg will free-flow for a moment when I first enter the water, the tank is seldom at a full 3000psi. With 19CF, I can lose a couple 100 psi and still have a useful pony. (It is also a lot of fun to use in the pool! No BC or weights, just the tank and a mask.)

I guess I'm glad I have it, but it is a PITA sometimes.

I also have chosen a backmounted 19cf - you clearly stated why. Thank you.

 

[elan]

What's wrong with independant twins as a redundant air source?

Increased task loading as you need to monitor 2 gauges and switch the regs every now and then to keep them balanced.

 

[Thalassamania]

Increased task loading as you need to monitor 2 gauges and switch the regs every now and then to keep them balanced.

I really can't see that glancing at two SPGs and swapping regulators twice is a huge increase in the task load of a diver; and that only pertains to diving rule of thirds (for an overhead situation). If you are diving independent doubles for redundancy in a normal open-water situation those procedures are entirely unnecessary since all you are trying to assure yourself is that there is sufficient gas in each of the tanks, at all times, to get you and your buddy back to the surface in a normal ascent.